holdsworth



(No Model.)

' f J. W. HOLDSWORTH.-

ELBGTRIG BELL.

' No. 575.156. y Patented Jan. 12,1189?.

21217272 tol/ UNITE il@ STATES FFICE@ i Arent JOI-INNV. IIOIiDSWORTI-I,` OF ST. LOUIS, MISSOURI, ASSIGNOR OF ONE-HALF TO ROBERT R. DODSVORTII, OF SAME PLACE; ROBERT R. DODSVORTII ADMINISTRATOR OF SAID I'IOIJDSWORTI'I, DEOEASED.

ELECTRIC BELL.

SPECIFICATION forming part of Letters Patent No. 575,156, dated January 12, 1897.

Application filed April 9, 1896. Serial No. 586,772. (No model.)

To @L7/Z whom it may concern,.-

Be it known that I, JOHN W. I-IoLDswoRTH, of the city of St. Louis, in the State of Missouri, have invented a certain new and useful Improvement in Electric Bells, of which the following is a full, clear, and exact description, reference being had to the accompanying drawings, forming a part of this specification.

My invention relates to an electric bell in which a stationary electromagnet is combined with an electromagnet wound-upon avibrating armature; and my invention consists in features of novelty hereinafter fully de- I 5 scribed, and pointed out in the claim.

Figure I is a top view of my improved bell.

Fig. II ,is a side elevation. Fig. III is a rear end view. Fig. IV is a top View of a modification. Figs. V and VI are respectively a zo side elevation and a rear end view of the modied form shown in Fig. IV.

In the drawings, 1 designates the base, and 2 the bell mounted thereon.

3 3iL designate the binding-posts.

4 designates a stationary electromagnetspool provided with extension pole-pieces 5 5, either one of which might be the positive and the other the negative, according to the direction in which the spool is Wound.

6 designates a bar, to the end 6a of which is secured a spring contact-plate 7, having a free end 8.

9 is a post that supports a contact-screw 10, provided with a set-nut Il. The point of 3 5 the screw l0 is presented to the contactplate 7.

l2 designates an arm secured to the bar 6,

the free end I3 of which arm is impinged by a lat spring I4, carried by the contact-plate 4o 7, said spring 14 passing through an opening l5 in the bar 6.

16 designates the armature-lever, secured at I7 to the contact-plate 7 and carrying at its free end a bell-hammer I8.

On the armature-leveris wound an electromagnet-spool 19, at the ends of which the inclosed portions 20 20l of the armature-lever form positive and negative pole-sections.

The spools 4 and 19 are wound in reverse 5o directions, and the consequent result is that the poles of one spool are located at opposite ends from that of the other spool and the pole of one name of one magnet opposite the I pole of the other name of the other magnet.

`and 19, and 22 is the return-wire.

In the operation of the bell the electric current enters the electromagnet-spools 4 and 19 by passing over the line-Wires 2l 21a, and the magnetism induced in the spools causes the attraction of the pole-sections of the armature-lever to the pole-pieces of the magnet- 7o spool 4.

By bringing the respective poles of the movable core into contact with those of opposite sign of the fixed core the magnetic circuit is closed through the two cores and the magnetic attractive force greatly increased.

In the modiiied form of device shown in Figs. IV, V, and VI, the electromagnet-spools 4n and 19a are wound in opposite directions, whereby the pole-piece 23 of the stationary 8o magnet-spool 4 is rendered of opposite name to the pole-piece 24 of the movable armaturemagnet 19a. In this form the spools are connected by a leaf-hinge 25, and the movement of the spool #19 is limited by a spring 2G, held, 8 5 by a set-screw 27.

I claim as my invention- In an electric bell, the combination of a iixed electromagnet comprising a bobbin and core, and a movable electromagnet compris- 9o ing a bobbin mounted upon a vibrating core, arranged parallel respectively to the fixed bobbin and core and having both the poles of said vibrating core arranged in magnetic relation to the poles of the fixed core of opposite sign; lateral extensions being provided on both the poles of one of the cores and at right angles thereto so as to bridge the space by which the cores are held apart by the bobbins and bring said cores in contacting rela- Ioo tion, and thus close the magnetic circuit between them, as explained.

JOI-IN W. IIOLDSVVOR'III.

In presence of E. S. KNIGHT, W. FINLEY. 

